An existing smallsize motor with reduction mechanism is described, for example, in the examined Japanese utility model application 50-9044. As shown in FIG. 9, the rotating shaft A of a motor is always coupled to the output shaft C via the reduction mechanism B. When a power is supplied to the excitation coil D, a rotating force of rotor E is transmitted to the output shaft C through the reduction mechanism B, thus driving a load. However, in the case of an existing motor, the rotating shaft A is always connected to the reduction mechanism B, and even when supply of power to the motor stops in order to release the load, the rotor E is rotated reversely only with a force of load because the rotor E of motor is coupled to the load, making it difficult to momentarily return the load to the original position. The load can be released momentarily, by providing the clutch mechanism between the motor and load and by connecting it when the motor rotates or by isolating it when the motor stops. But a particular drive source is required for coupling and isolation of clutch, resulting in cost-up. In addition, control of clutch is difficult because it must be connected or isolated by such a drive source accurately in accordance with start and stop of motor rotation.